The present invention relates to transmission of information packets, and more particularly, to aligning and determining data packets for transmission of data over a network channel.
Data, e.g. an image, transmitted over a network may travel through several layers based on Transmission Control Protocol/Internet Protocol (TCP/IP) reference model. These layers may include application, transport, network, data link, and physical layers. Each layer may add a header to address data parameters.
FIG. 1 illustrates an exemplary layering and encapsulation structure 100. For example, an application layer image 102 may be digitized and compressed. The compressed image may then be segmented and encapsulated into several Real-time Transport Protocol (RTP) packets 104 residing at the transport layer.
In some cases, the data may be segmented into independent decoding units (IDU) prior to compression to reduce error propagation during compression and transmission. Each RTP packet 104 may include a 12-byte header 106. The RTP packet 104 may further be encapsulated into a Transmission Control Protocol (TCP) or User Datagram Protocol (UDP) packet 108. At the next lower layer, e.g. the network layer, each TCP/UDP packet 108 may be encapsulated into an Internet Protocol (IP) packet or datagram 110. Each IP datagram 110 may then be fragmented into one or more frames 112 at the data link layer, such as Layer 2. However, difficulties associated with this structure 100 include the loss or corruption of a single frame at the data link layer propagating into successively higher layers to invalidate a large number of packets.